As a closure to the series's emotional arc, I thought it was great. And I enjoyed the new culture and viewpoint character. As in the previous books, I though Monette's character voices were clear and distinct and the overall prose smooth. But I haven't the faintest understanding of what Felix actually does at the end to destroy the Summerdown machine. The machine feeds on death, so he feeds it a spirit of vengeance and it chokes? Huh? I realize blasting it with a lightning bolt, as he did the other machine, would be anti-climactic (though I would have appreciated a better explanation in the text of why it wouldn't work, or at least why Felix didn't think it was worth trying), but the alternate was simply incomprehensible to me.
Also, I wasn't thrilled to see Felix returning to prostitution to make money. Yeah, I know, Monette likes to torture her characters and Felix canonically likes to torture himself. But he couldn't think of anything else? Telling fortunes, say? Mildmay's later mention that he should have pawned his rings instead confused me more. At that point in the story, isn't Felix completely unaware that Shannon gave Mildmay Felix's rings?